Bone grafting is a surgical procedure by which new bone or a replacement material is placed into spaces between or around fractures or holes in bone (bone defects) to aid in healing. Bone grafting is used to repair bone fractures that are extremely complex, pose a significant risk to the patient or fail to heal properly. Bone graft is also used to help fusion between vertebrae, correct deformities or provide structural support for fractures of the spine. In addition to fracture repair, bone graft is used to repair defects in bone caused by birth defects, traumatic injury, or surgery for bone cancer.
A wide variety of bone graft materials have been used and/or suggested in the art for the treatment of bone defects. Traditional bone grafting has included the use of autograft bone or allograft bone. In addition to traditional bone grafting, a number of synthetic bone graft substitutes have been used or explored, including some materials that contain ceramics, calcium phosphates or demineralized bone matrix (sometimes referred to as “DBM”). DBM is demineralized allograft bone with osteoinductive activity. Demineralized bone matrices are prepared by acid extraction of allograft bone, resulting in the loss of most of the mineralized component but retention of collagen and noncollagenous proteins including growth factors. The efficacy of a demineralized bone matrix as a bone-graft substitute or extender is due to the presence of bone morphogenetic protein (BMP) as well as the ratios of the different BMPs present. BMPs belong to the transforming growth factor (TGF) superfamily of proteins. DBM has been shown to exhibit the ability to induce and/or conduct the formation of bone. It is thus desirable to implant and maintain demineralized bone matrix at a site at which bone growth is desired.
However, the beneficial nature of demineralized bone matrix is susceptible to disruption by the incorporation of incompatible materials or techniques when formulating a medical implant. At the same time, it is desirable to have implant devices exhibiting good physical integrity to retain the demineralized bone matrix at the implant site, and that handle well in the operating environment and during implantation. In addition, it is of considerable commercial significance that the medical implant be manufacturable without undue cost, equipment or material burdens. Accordingly, there exist needs for product configurations including DBM which exhibit the ability to induce and/or support bone growth through the desired region, which are readily manufacturable and which demonstrate acceptable handling properties for surgeons.